Evaluation of Anti-Malarial Effects of Mass Chemoprophylaxis in the Republic of Korea Army

Abstract

Vivax malaria was endemic on the Korean peninsula for many centuries until the late 1970's when the Republic of Korea (ROK) was declared "malaria free". Since its re-emergence in 1993, the number of malaria cases in the military increased exponentially through 2000 near the demilitarized zone. Chemoprophylaxis with chloroquine and primaquine has been used in the ROK Army since 1997 in an attempt to reduce the number of the malaria cases throughout the ROK. Data show that chemoprophylaxis contributed, in part, to the decrease in the number of malaria cases among military personnel. However, mass chemoprophylaxis on a large scale in the ROK Army is unprecedented and extensive supervision and monitoring is warranted to determine its effectiveness and to monitor the appearance of chloroquine tolerant/resistant strains of Plasmodium vivax.

Plasmodium vivax Malaria: Status in the Republic of Korea Following Reemergence

“…To calculate the chemoprophylactic efficacy, the occurrences of P. vivax malaria were compared between paired units with the similar risk for the exposure to infected Anopheline mosquitoes. In the treatment groups (those receiving chemoprophylaxis), a significant reduction in number of malaria cases was demonstrated while in their paired control group (no chemoprophylaxis) the number of cases increased significantly (Table 4) [16]. These results also demonstrate that even with partial chemoprophylaxis in malaria high-risk areas, the incidence of malaria decreased while expanding in adjacent counties where chemoprophylaxis was not provided.…”

“…From 1999 through 2002, the prevalence of malaria in the military population began to decrease 1-2 weeks after the initiation of chemoprophylaxis in early June or mid-May. This finding was different that the steadily increasing cases of malaria cases among civilians not provided with (Table 3) [16].…”

“…Chemoprophylaxis has involved hydroxychloroquine (HCQ), which is an analogue of chloroquine (CQ) with equivalent activity against malaria to CQ, followed by presumptive anti-relapse therapy with primaquine (PQ). The chemoprophylaxis program was expanded annually from approximately 16,000 soldiers in 1997 to 200,000 soldiers in 2005 (Table 2) [16]. Decreased incidence of P. vivax malaria in the ROK military was attributed to the annual expansion of chemoprophylaxis in high-risk malaria areas, especially since 1999.…”

“…Cases in these regions gradually decreased to 56% by 2002 (Table 3) [16]. To calculate the chemoprophylactic efficacy, the occurrences of P. vivax malaria were compared between paired units with the similar risk for the exposure to infected Anopheline mosquitoes.…”

Chemoprophylaxis and the epidemiological characteristics of re-emergent P. vivax malaria in the Republic of Korea

“…4,9 Malaria cases in veterans are defined as those experiencing a malaria attack within 24 months after retiret t ment. Soldiers diagnosed with malaria are admitted to a military hospital for treatment and are interviewed by physit t cians; veterans are treated in community outpatient clinics and are interviewed by trained publicthealth specialists.…”